Soil erosion prediction using the Revised Universal Soil Loss Equation (RUSLE) in a GIS framework,Chania, Northwestern Crete,Greece

Soil erosion is a growing problem in southern Greece and particularly in the island of Crete, the biggest Greek island with great agricultural activity. Soil erosion not only decreases agricultural productivity, but also reduces the water availability. In the current study, an effort to predict potential annual soil loss has been conducted. For the prediction, the Revised Universal Soil Loss Equation (RUSLE) has been adopted in a Geographical Information System framework. The RUSLE factors were calculated (in the form of raster layers) for the nine major watersheds which cover the northern part of the Chania Prefecture. The R-factor was calculated from monthly and annual precipitation data. The K-factor was estimated using soil maps available from the Soil Geographical Data Base of Europe at a scale of 1:1,000,000. The LS-factor was calculated from a 30-m digital elevation model. The C-factor was calculated using Remote Sensing techniques. The P-factor in absence of data was set to 1. The results show that an extended part of the area is undergoing severe erosion. The mean annual soil loss is predicted up to ∼200 (t/ha year⁻¹) for some watersheds showing extended erosion and demanding the attention of local administrators.     

RS技术在实时区域土壤侵蚀评价中的应用--以福建省花山溪流域为例

传统数据采集方法严重制约了土壤侵蚀评价实时、快速的要求。文章以福建花山溪流域为例,基于“通用土壤侵蚀方程式”(USLE)为土壤侵蚀定量评价模型,利用多时效、多光谱的遥感数据,在ERDAS8．5软件平台上,研究提取流域动态最易变化的植被、土地利用类型等信息的技术方法。研究结果证实,这种方法可以快速、准确地提取影响土壤侵蚀的基本参数．进而实现对区域流域土壤侵蚀的实时评价。     

陇东地区水土流失与地质作用初步分析

陇东地区是黄河上游水土流失严重区 ,也是国家重点治理的地区之一。由于特殊的岩土体的存在 ,加重了这一地区水土流失作用的危害性。本文通过水土流失现象与地质作用的关系进行偿试性探讨 ,旨在从中找到防治水土流失的有效措施 ,开展治理工作     

贵州鹅项水库沉积物特征及其土壤侵蚀的意义

对位于贵州西南部非喀斯特丘原区的鹅项水库中取得的一沉积物样芯（EX-1）做了¹³⁷Cs,TOC,C/N和粒度分析以及矿物磁性测量。通过对这些分析和测量结果进行解译,推测了在过去的45年（1960～2005年）中这一水库的汇水流域内土壤侵蚀强度的相对变化。在这45年中,鹅项水库流域的土壤侵蚀经历了由弱到强再持续减弱的一个过程。将这一推测结果与流域内降水数据和土地利用/覆被变化资料数据相结合,探究了该流域土壤侵蚀强度变化的原因。与贵州西南部典型喀斯特流域的情况相比,在鹅项流域内,土地利用/覆被变化情况对土壤侵蚀强度的影响相对次要,而降水对土壤侵蚀强度变化的影响则更为重要。这可能主要因为与典型喀斯特流域相比,鹅项流域的土层较厚、植被覆盖较好。     

重庆市岩溶区县土地利用景观破碎化及土壤侵蚀影响评价

根据重庆岩溶区县土地利用景观破碎情况,采用双向指示种分析法和除趋势典范对应分析法对研究区县及各土地利用类型进行分类和排序,揭示其空间分布的景观生态学意义及土壤侵蚀对土地利用景观破碎化的影响。根据分析结果, 可将研究区22种土地利用类型分为未利用地、平原耕地、山地耕地和灌草地4大类;可将研究区25个区县样方可分为低脆弱剧烈破碎区;低脆弱极强破碎区;低脆弱强破碎区;中脆弱中强破碎区;重脆弱中破碎区;重脆弱轻破碎区;中脆弱微破碎区7个样方群,空间上它们分属于渝东部、渝中部和渝西部3个区域,其土壤侵蚀性从东往西逐渐减弱。除趋势典范对应分析结果表明,较强的土壤侵蚀会加剧土地利用景观的破碎化,加剧破碎化的强度同土壤侵蚀等级呈现出相反的趋势。      

盐渍土化学潜蚀溶陷过程阶段化模型分析

将盐渍土化学潜蚀溶陷变形过程划分为3状态2阶段进行分析,并根据阶段变化规律总结出不同状态时土体物理指标间的相互关系.通过该关系分析出盐渍土溶陷发生的关键阶段,并推导了盐渍土溶陷系数与溶陷前后土体物理指标间的数量关系.分析并验证了土体的孔隙比、含盐率以及土体的结构组成形式都是影响盐渍土潜蚀溶陷变形的重要因素.     

湖北省土壤侵蚀景观空间异质性及驱动因子分析

地域分异是地球表层大小不等、内部具有一定相似性地段之间的相互分化以及由此产生的差异。为了研究不同区位土壤侵蚀问题，从土壤生态景观及系统论出发，运用地质学、地理学、景观生态学、环境学的理论和研究方法，研究湖北省土壤侵蚀景观空间格局及其驱动因子，使土壤侵蚀问题研究提高到一个新的水平。湖北省土壤侵蚀景观具有南北分带、东西分区，为一不对称的断块一环组合，土壤流呈现向长江、江汉盆地中心轴带辐聚、单流向特点。景观空间异质性形成的首要驱动因子是大地构造背景，以房县一襄樊一广济断裂带为界，南北两侧地壳物质组成和构造发展史存在较明显的差异，现代气候带、降雨量、温热程度及土地利用等差异，造成了湖北省区域土壤地理、土壤生态的分异，形成湖北省土壤生态带、区具有南北分带，东西分区的宏观格局；其次大兴安岭一武陵山深部构造陡变带两侧新构造运动强度差异、大别造山带构造强烈隆升，导致土壤侵蚀强度的西强东弱、南北强中间弱的态势；成土母岩差异性决定了土壤可蚀性的多变；空间上“土壤侵蚀内城区”分布在湖北省的周边地区，经济贫困、管理落后，这一地区的经济水平与水土流失间形成“自反馈作用”，这一现象在我国水土保持、生态建设工作中应该引起重视。     

Discussion on Coastal Erosion Near Xizhuang, Penglai, China

-In this work, on the basis of the characteristics of coastal erosion near Xizhuang (Penglai, Shandong, China) and the in-situ measured data and theoretical calculation, the causes of coastal erosion there are obtained: (1) natural erosion, (2) beach sand borrowing, and (3) sand borrowing at the Dengzhou shoal near Xizhuang, which results in the loss of the function of the wave force resistance of the shoal. Since the wave energy is increased, the longshore sediment transport rate is increased. Coastal erosions are more and more serious. A scientific basis to reduced the calamity of coastal erosion in local area is presented. Some experiences are accumulated for studying coastal erosion.     

Equilibrium erosion of soft rock shores with a shallow or absent beach under increased sea level rise

A process-based numerical model was used to explore the response of soft rock shores with low volume beaches to variable rates of sea level rise. Equilibrium recession rates were simulated for ranges of wave height and period, tidal amplitude, rock strength, beach volume and rate of sea level rise. Equilibrium shore profiles were found to be steeper with higher rates of sea level rise. Beaches were represented as protective surfaces yet were found to cause no significant reduction in equilibrium recession rate when their volumes were below a critical threshold. Reduced equilibrium recession rates were found with beaches that extended sufficiently far below low tide level. The model results imply that, given several constraints, a very simple relationship exists between increased rates of sea level rise and the response of eroding composite soft rock/low volume beach shores.     

渭河流域东部全新世黄土-古土壤剖面光释光测年及其记录的土壤侵蚀事件

在渭河流域东部老官台(LGT)全新世黄土-古土壤剖面中,系统采集了15个黄土释光测年样品,应用单片再生剂量法(SAR)对这些样品的细颗粒混合矿物进行了光释光(OSL)测年,测定结果表明:红外之后蓝光释光([post-IR]OSL)的年龄偏大,红外释光(IRSL)的年龄偏小或与蓝光释光(BLSL)的年龄基本一致,应用IRSL和BLSL信号测定的OSL年龄整体偏小可能与测定样品中长石矿物的异常衰退有关,而[post-IR]OSL信号由于很少发生异常衰退问题,使得其年龄可靠性更高。基于测定的[post-IR]OSL年龄,结合该剖面的磁化率和粒度指标,进一步探讨了渭河流域东部自全新世以来发生的两期土壤侵蚀事件,第1期土壤侵蚀事件发生在约12.40~9.34kaBP,即全新世大暖期来临之前的气候转暖期间;第2期土壤侵蚀事件发生在约4.60~3.76kaBP,即全新世大暖期即将结束、气候开始出现恶化、黄河中游地区夏文化发展的时期,这为深入探索夏代发生的大洪水事件及其气候背景提供了科学依据,本区两期显著的土壤侵蚀事件的发现,揭示了东亚季风系统的不稳定性,表现为千年到百年尺度上的快速变化。